Central Pacific Basin Tropical Cyclones

Hurricane Dora Forecast Discussion

WTPA42 PHFO 100245

Hurricane Dora Discussion Number  39
NWS Central Pacific Hurricane Center Honolulu HI   EP052023
500 PM HST Wed Aug 09 2023

Dora has begun to slowly gain latitude this afternoon, as forecast, 
but has strengthened once again within a low-shear and marginally 
warm sea surface temperature environment. Satellite presentation 
has improved from late this morning, with a clearly defined 8 nm 
wide eye and a symmetrical central structure. The central dense 
overcast feature around the core is less than 100 nm wide, giving 
Dora an increasingly annular appearance. This intense but compact 
system is only about 240 nm wide from north to south, including all 
banding features. All three fix agencies derived subjective Dvorak 
intensity estimates of 6.5, corresponding to 127 kt. Latest UW-CIMSS 
ADT is 122 kt. Given these derived intensity values, Dora is given 
an initial intensity of 125 kt for this advisory, keeping her as a 
solid category 4 tropical cyclone.

Initial motion with this advisory is 275/19 kt, unchanged from the
last two advisories. Like before, track guidance remains remarkably 
tight through tau 72, with spread only becoming significant at tau 
96 and beyond, long after this system has passed out of the basin 
into the western North Pacific. The larger synoptic environment 
around Dora remains unchanged. Strong ridging north of Dora, and 
the westward migration of this ridging, accounts for this system's 
prolonged westward movement. However, the slow and recent increase 
in latitude indicates that Dora is reaching the southwest flank of
this ridging. Dora is forecast to continue gaining latitude and 
assume a northwest motion Thursday and Friday. The forecast track, 
closely following the previous track and TVCN model consensus, 
continues to become more northerly after Dora passes west of the 
date line.

Warm water, with temperatures of 28 degrees C or above, lies along
the entire forecast track and shear will remain less than 20 kt 
through tau 60. With 00Z ECMWF SHIPS showing almost no Dora 
intensity drop through tau 24, this advisory will only slowly 
weaken this system through tau 36, with more pronounced weakening 
introduced afterwards as Dora gains latitude and shear increases. 
The 00Z GFS SHIPS shows a similar slow weakening trend through tau 
24, with more rapid weakening afterwards. As before, both SHIPS
versions keep Dora stronger at all tau than most intensity model
guidance. However, given that Dora insists on strengthening within 
the environment it is in, forecasting a slower weakening trend, at 
least initially, seems reasonable. Dora will eventually weaken to a 
post-tropical/remnant low, but after tau 120.


INIT  10/0300Z 11.8N 167.9W  125 KT 145 MPH
 12H  10/1200Z 12.0N 170.8W  120 KT 140 MPH
 24H  11/0000Z 13.1N 174.4W  115 KT 130 MPH
 36H  11/1200Z 14.4N 177.9W  115 KT 130 MPH
 48H  12/0000Z 15.3N 179.1E  110 KT 125 MPH
 60H  12/1200Z 16.1N 176.2E  105 KT 120 MPH
 72H  13/0000Z 16.8N 173.2E   95 KT 110 MPH
 96H  14/0000Z 18.1N 168.0E   70 KT  80 MPH
120H  15/0000Z 20.7N 164.2E   50 KT  60 MPH

Forecaster Powell

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